Boat hull with tunneled v-bottom



H- J. DORNAK July 11, 1967 BOAT HULL WITH TUNNELED V-BOTTOM 4Sheets-Sheav 1 Filed Sept.

Henry J. Dornalr INVENTOR.

July 11, 1967 Filed Sept. 3, 1964 H. L DCDRFJAP BOAT HULL WITH TUNNELEDV-BOTTOM Fig. 3

4 Sheets-Sheet 2 Henry J Oornak IN VENTOR.

J ly 1957 H. J. DORNAK 3,330,239

BOAT HULL WITH TUNNELED V-BOTTOM Filed Sept. 5, 1964 4 Sheets-Sheet 5Henry J Darna/r INVENTOR.

M4052 BY m, vm

July 11, 1967 H. J. DORNAK 3,330,239

BOAT HULL WITH TUNNELED V-BOTTOM Filed Sept. 5, 1964 4 Sheets-Sheet 4Henry .1. Dorna/r 1 N VEN TOR.

United States Patent 3,330,239 BOAT HULL WITH TUNNELED V-BOTTGM Henry J.Dornak, 601 S. Mechanic St., El Campo, Tex. 77437 Filed Sept. 3, 1964,Ser. No. 394,253 21 Claims. (Cl. 114-56) This invention relates to anovel and useful boat hull of the type including a forward upwardly andforwardly curving bow portion and a substantially longitudinallystraight planing portion. The planing portion of the bottom of the boathull of the instant invention defines a longitudinal centerline and atleast one pair of downwardly opening generally inverted V-shaped andlongitudinally straight lift tunnels which extend along opposite sidesof the longitudinal centerline of the bottom. Each of the tunnelsincludes inner and outer downwardly divergent surfaces including majorportions that are substantially planar and corresponding longitudinaledge portions of the inner surfaces of the tunnels are disposed in afirst plane spaced below a second plane containing the lowerlongitudinal marginal edge portions of the corresponding outer surfaces.In this manner a basically V-shaped hull is formed and yet a hullincluding longitudinally extending and downwardly opening tunnels which,in addition to trapping air in the forward portion thereof and providinga means for cushioning the ride afforded by the boat hull, give rise tomany advantages of operation as a result of their particularconfiguration as will hereinafter be more fully set forth.

The main object of this invention is to provide a boat hull which isbasically V-shaped in transverse vertical section and which includeslongitudinally straight and downwardly opening generally invertedV-shaped tunnels disposed on opposite sides of the longitudinalcenterline of the hull.

Another object of this invention, in accordance with the immediatelypreceding object, is to provide each of the tunnels with a smoothly andforwardly and upwardly curving forward portion disposed in the bowportion of the hull and which, when the boat hull is moving at highspeed, will increase the lift of the hull in a manner such that only anarrow center strip of the planing surfaces of the hull are disposed incont-act with the water when the hull is moving at high speed therebyappreciably reducing the wetted area of the hull and thus the hull towater friction, therefore increasing speed as compared to conventionaldesigns.

Still another object of this invention is to provide the downwardlyopening tunnels of the boat hull of the instant invention withdownwardly divergent opposite side surfaces which are substantiallyplanar and form an included angle exceeding 90 degrees. With this typeof construction forward movement of the hull through the water and thedownward thrust of the hull on the water will cause the upwardlyand'outwardly inclined inner surfaces of the tunnels to cause water tobe rapidly displaced upwardly and outwardly along the inner surfaces ofthe tunnels and toward the downwardly and outwardly inclined outersurfaces of the tunnels thereby enabling the momentum or kinetic energyof the water displaced to apply a lifting thrust on the outer surfacesof the tunnels, thereby allowing the hull to carry greater load perhorse power than conventional designs. In most instances, because of thedesired overall V-shaped configuration of the hull, the upwardly andoutwardly inclined inner surfaces of the tunnels will be of considerablygreater width than the downwardly and outwardly inclined outer surfacesof the tunnels and in addition the upwardly and outwardly inclined innersurfaces of the tunnels will be disposed at a greater angle relative toa vertical plane than 3,330,239 Patented July 11, 1967 the downwardlyand outwardly inclined outer surface of the tunnels.

Yet another object of this invention is to provide a tunneled boat hullconstruction which is basically V- shaped in transverse cross-sectionand which includes structural features which adapt the hull for use incalm water as well as rough water.

Another object of this invention, in accordance with the immediatelypreceding object, is to provide a boat hull construction includinglongitudinally extending and downwardly opening generally V-shapedtunnels disposed relative to each other and including inclined surfaceswhich adapt themselves for slight variations in construction and designin a manner enabling a basic design of boat hull to be followed withonly slight modifications thereto being required to specifically adaptthe boat hull for use in smooth or rough water and to be utilized tocarry heavy or light loads.

Still another object of this invention is to provide a boat hullconstruction that is well suited for inboard as well as outboard motorinstallations and which is further well suited for use in constructionof inboard bulls and Outboards hulls as well as sea plane hulls andother planing apparatus.

Still another object of this invention is to provide a boat hullconstruction including structural features which specifically adapt theboat hull to afford an air cushioned ride while simultaneously reducingthe wetted area of the hull.

A further object of this invention is to provide a boat hull includingstructural features that enable any and all water displaced transverselyoutwardly away from the longitudinal centerline of the hull in responseto rapid forward movement of the hull over a body of water to bedeflected downwardly as opposed to upwardly and outwardly therebyproviding a boat hull which is extremely dry.

Yet another object of this invention is to provide a boat hullconstructon including structural features adapting the hull for use withsingle propeller installations as well as dual propeller installationswhile simultaneously providing the desired V-shaped hull and alsoreducing the draft of the boat hull relative to the draft of aconventional V-shaped hull.

Another object of this invention is to provide a boat hull constructionthat due to the tunnels and tunnel surfaces maintains positive controland maneuverability in any type of seat at any speed range.

Another object of this invention is to provide a boat hull constructionincluding structural features that provide superior stability to thecraft at rest and in motion.

Another object of this invention is to provide a boat hull constructionincluding structural features which due to their configuration lendsadditional inherent strength to the bottom material, therefrom providinga stronger bottom structurally than conventional hull designs.

Another object of this invention is to provide a boat hull constructionincluding structural features that allow ram air to enter beneath thehull and become trapped and compressed and as it passes aft along thehull to cushion the ride and break up skin friction on the tunnelsurfaces.

A final object of this invention to be specifically enumerated herein isto provide a tunneled V-bottom boat hull in accordance with thepreceding objects which will conform to conventional forms ofmanufacture, be readily adaptable to minor configuration variations andhighly eflicient in operation so as to provide a hull that will beeconomically feasible, readily adaptable for use 0n rough and smoothwater and for maximum speed and stability.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of ii construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURE 1 is a bottom plan view of the boat hull of the instantinvention;

FIGURE Z is a side elevational view of the boat hull of the instantinvention;

FIGURE 3 is a front elevational view of the boat hull of the instantinvention shown on somewhat of an enlarged scale; 7

FIGURE 4 is a diagrammatical view of the cross-sectional shape of theboat hull of the instant invention illustrating the manner in which theboat hull affords exceptional stability while executing a turn;

FIGURE 5 is a diagrammatical view of the cross-sectional shape of theboat hull of the instant invention showing the manner in which it isparticularly well adapted for dual motor installation and also themanner in which the overall draft of the .boat hull is substantiallyreduced by its particular configuration and its adaptability for dualmotor installation;

FIGURE 6 is a further diagrammatical view of the cross-sectional shapeof the center portion of the boat hull of the instant inventionillustrating the manner in which it is particularly well adapted forsingle motor installation and also the manner in which the draft of theboat hull of the instant invention is reduced relative to the draft of aconventional V-bottorn hull including a single propeller;

FIGURE 7 is still another diagrammatical view of the cross-sectionalshape of the boat hull of the instant invention but showing a slightlymodified cross-sectional contour;

FIGURES 8 and 9 are two additional diagrammatical views of two furthermodified cross-sectional shapes of the boat hull of the instantinvention;

FIGURE 10 is yet another'diagrammatical view of the cross-sectionalshape of a hull constructed in accordance with the present invention andillustrating a further modification thereof including a center generallyV-shaped wedge and also illustrating the manner in which the wetted areaof the boat hull is progressively reduced as the speed a of the hullover the surface of a body of water is increased and'also with stillanother modification of the cross-sectional shape of the hullillustrated in phantom lines;

FIGURE 11 is a diagrammatical view of the cross-sectional shape of theboat hull of the instant invention similar to that of FIGURE 10 butshowing another modified form of boat hull;

FIGURE 12 is a diagrammatical view of the cross-sectional shape of yetanother form of boat hull constructed in accordance with the presentinvention which defines a deeper V-shaped hull; and 7 FIGURE 13 is adiagrammatical view of the cross-sectional 'shape of the ,boat hullconstructed in accordance with the present invention and with a furthermodified form of boat hull shown in phantom lines.

Referring now more specifically to the drawings the numeral 10 generallydesignates the boat hull of the instant invention which may be seen toinclude opposite sides 12 and 14 interconnected by means of a transom 16and a bottom generally referred to by the reference numeral 18 includinga forwardly and upwardly curving bow portion 20 and a substantiallylongitudinally straight planing portion 22. The bottom 18 defines alongitudinal centerline 24 and a plurality of downwardly opening andlongitudinally extending generally inverted V-shaped tunnels 26, 28and'30. The tunnels 26, 28, and are sub Vstantially straight in theplaning portion 22 and include forward extensions 26', 28' and 30 whichsmoothly curve forwardly and upwardly in the bow portion 20, theextensions 28' and 30 also curving inwardly toward the center tunnel 26.Tunnels 28 and 30 plus any additional lift 7 and stability tunnels whichsmoothly curve forwardly and r 4 upwardly may also be run substantiallyparallelto the longitudinal centerline in ing the performancecharacteristics to any extent.

With attention now invitedto FIGURE 12 of the drawings there may be seena modified form of boat hull generally referred to by the referencenumeral 32 and which includes a center tunnel 34 corresponding to thetunnel 26 and a first pair of opposite side tunnels 36 corresponding tothe opposite side tunnels 28. The tunnels 36 and 28 define lift tunnelsand it may be seen that the hull 32 additionally includes a second pairof lift tunnels 38. Then, disposed outwardly of the second pair of lifttunnels 38 the hull includes a pair of inner stabilizing tunnels 40correspondingto the stabilizing tunnels 30 and a second pair of outerstabilizing tunnels 42.

Each of the tunnels 36, 38, 40 and 42 includes a pair of downwardlydivergent opposite side inner and outer surfaces A and B. The includedangles formed between corresponding inner and outer surfaces A and B isgreater than 90 and it may be seen by the arrows disposed in the tunnels36, 38, 40 and 42 at the left side of FIGURE 12 that any downward forceof the boat hull 32 on a body of water while the boat hull 32 istraveling at good speeds will cause quantities of water to be rapidlydisplaced upwardly and outwardly along the inclined inner surfaces A andto be directed against the downwardly and outwardly inclined surfaces Bthereby enabling the hull construction 32 to harness the kinetic energyof'the laterally and a upwardly displaced water impinging upon thedownwardly and outwardly inclined outer surfaces A to apply an upwardlifting force on the hull construction32.

With attention now invited to FIGURE 11 of the drawings there may beseen a modified form of boat hull construction generally referred to bythe reference numeral 46 and which is similar to the hull construction32. Horizontal broken lines C, D and E designate the water lines of thehull construction 46 while traveling at slow speeds, intermediate'speedsand high speeds, respectively. It is believed that it may be readilyappreciated that the greater the speed of the hull construction 46 thegreater will be the upward lifting force of the water applied to thehull construction 46 as explained above in connection with theharnessing of the kinetic energy of the water displaced upwardly andoutwardly along the inner surfaces A and impinging upon the outersurfaces B plus the air lift and kinetic water lift imparted on thecenter tunnel, the air being compressed and acting as a shock absorbercushioning the ride and breaking up ,skin friction on its surfaces.

Although extreme cases may prove exception" to the rule, the downwardlyand outwardly inclined outer surfaces B are to be disposed at an anglefalling between 40 and degrees from a vertical plane and therefore thesurfaces A, the inner surfaces of the tunnels, are disposed at an angleinclined at least 10 degrees from a horizontal plane.

It may be noted that the boat hull construction 46 illustrated in FIGURE11 of the drawings includes a center tunnel 50 but that a similar hullconstruction illustrated in FIGURE 10 of the drawings and generallydesignated by the reference numeral 52 includes a center generallyV-shaped wedge 54 in lieu of the center tunnel 50. The

center V-shaped wedge 54 may be utilized in lieu of the center invertedV-shaped tunnel when a boat hull is de signed with at least one'pair oflift tunnels and one or more pairs of stability tunnels. The terms liftand stability. as referred to the tunnels is used for clarity and areintera changeable. Each tunnel acts as a lift and/or stability tunnel. i

The water levels or lines F, G and H shown in FIG- URE 10 of thedrawings further illustrate the manner in which the kinetic energy ofthe laterally and outwardly displaced water caused by forward movementofthe hull constructed in accordance with the present invention may beharnessed by the outer downwardly and outwardly inbow portion 20 withoutchang clined surfaces of the tunnels and utilized to eflfect an upwardlifting force on the hull which increases as the forward speed of thehull increases.

With attention now directed to FIGURES 5 and 6 of the drawings there maybe seen diagrammatically illustrated a pair of marine propellers 54 and56 shown in their positions partially embraced in the lifting tunnels 58disposed on opposite sides of the center tunnel 60 of the hullconstruction generally referred to by the reference numeral 62. Theoutline of a conventional V-shaped hull is generally designated by thereference numeral 64 and it may be seen that a dual propellerinstallation diagrammatically illustrated by the phantom line showingsof the propellers 66 and 63 requires considerably more draft. Inaddition, a single propeller installation may be seen to be illustratedin FIGURE 6 of the drawings by the diagrammatical showing of thepropeller 70 partially embraced by the center tunnel 72 of a hullconstruction generally referred to by the reference numeral 74. Theoutline of a conventional V-shaped hull is also illustrated in FIGURE 6of the drawings by phantom lines 76 and an accompanying single marinepropeller is designated by the reference numeral 78. The increase indraft of the conventional V-shaped hull construction provided with asingle propeller installation over the draft of the hull construction 74provided with a single propeller installation is designated by thedistance J. Therefore, it may be seen from a comparison of FIGURES 5 and6 of the drawings that a hull construction in accordance with thepresent invention and including a center tunnel is particularly welladapted for shallow draft operation with dual propellers and that thesame type of hull construction is also particularly well adapted for usewith single propeller installation and also provides a reduced draft ascompared to the draft of a conventional boat hull construction utilizinga single propeller installation.

With attention now directed to the modified hull constructionillustrated in FIGURES 8 and 9 of the drawings and generally referred toby the reference numerals 80 and 82, it may be seen that the lowerlongitudinal edge portions of the cut waters 84 defined between adjacenttunnels of the hull construction 80 are generally semi-cylindrical inconfiguration. Additionally it may be seen from the showing in FIGURE 9of the drawings that the tunnels of the hull construction 82 areseparated by means of generally horizontal longitudinally extendingnarrow planing surfaces 86.

Although the lower portions of the cut waters defined between adjacenttunnels of the hull constructions 80 and 82 are somewhat modified, theoperation of these hull constructions remains substantially the same asthe hull constructions disclosed herein which are substantially V-shapedin transverse outline.

With attention now directed to FIGURE 7 of the drawings there may beseen a still further modified form of hull construction generallyreferred to by the reference numeral 90 and which includes a pluralityof longitudinally extending tunnels which are generally inverted V-shaped in cross-section but which include generally semicylindricalapices 92, 94, 96 and 98. Again, while the cross-sectional outline ofthe tunnels of the hull construction 90 has been modified to somedegree, the operation of the hull construction 90 remains substantiallythe same as the other hull constructions disclosed herein.

In FIGURE 4 of the drawings a hull construction generally referred to bythe reference numeral 100 and generally corresponding to the hullconstruction is illustrated and is shown executing a turn at high speedwith the centrifugal forces caused by the high speed turn beingindicated by the arrow 102. The inner tunnel surface 104 is beingadvanced against the water 106 and acts to upwardly deflect the side ofthe boat hull construction 100 on the outside of the turn by its planingaction with the water 106 and by deflecting the water upwardly and intoimpingement with the corresponding outer side tunnel surface 108. Thisupwardly deflected water is strapped by the outer side tunnel surface108 causing the tunnel to be filledwith water and, therefore, supplyinga constant volume of water to the outboard propeller while turning. Inthis manner cavitation and thus loss of power is sequenced.Additionally, it will be noted that the outer tunnel side surface 108 isstill downwardly and outwardly inclined and therefore that the sprayeffected by the boat hull construction executing a turn at high speed isdeflected downwardly toward the surface of the water 106. Additionally,it will be noted that the outer surfaces 110, 112 and 114 of the tunnels116, 118 and 120 act as keels to minimize side slipping of the hullconstruction 100 while the latter is executing the turn at high speed.

With attention now invited to FIGURE 13 of the drawings there may beseen yet another modified form of hull construction generally referredto by the reference numeral 124. The hull construction 124 includes acenter tunnel 126, two pairs of opposite side lift tunnels 128 and 130and two pairs of opposite side stabilizing tunnels 132 and 134. Thetransverse width of the outer surface 136 of the tunnel 128 on therighthand side of FIGURE 13 is designated as an unknown distance Y. Thecorresponding inner surface 138 has a transverse width greater thanthree times the width Y. Although variations in the ratio of the widthof the surfaces 138 and 136 may vary, it is to be noted that this ratiowill be at least 2 to 1. In addition, it may be seen that the transversewidth of the outer side of the tunnel 128 disposed on the lefthand sideof the figure is designated as X and that the transverse width of theinner side of the tunnel 128 on the lefthand side of FIGURE 13 isdesignated as greater than four times X and not less than 2 to 1. Again,although the ratio between the transverse width of the inner and outersides of the tunnels of the hull construction 124 may vary, it is to beunderstood that this ratio will not exceed 5 to l.

All of the various tunnels of the various hull constructions disclosedherein fall within these ratio limits and these ratio limits have beenfound to offer the most desired operational advantages of hullconstructions constructed in accordance with the present invention.Additionally, it is to be noted that the included angles formed bycorresponding inner and outer surfaces of all of the tunnels disclosedherein are greater than 90 degrees as previously set forth in connectionwith the hull construction 32 illustrated in FIGURE 12 of the drawings.Still further, the phantom line illustration in FIG- URES 6, 7 and 10-13illustrate further modified forms of hull constructions which include onless pair of tunnels than the corresponding form of the inventionillustrated in solid lines.

In actual controlled tests as a result of the construction and testingof numerous hull constructions such as those illustrated in the presentinvention and other modifications operating on the same principles oflift as described herein, it has been found that the hull constructionthat is provided with a deeper overall V in transverse section as isillustrated in FIGURE 12 as compared to a shallower overall V intransverse section as in FIG- URE 13 operates in a superior manner inrough water at sea. The converse of these situations would thenobviously also apply with a shallower V-shaped hull. The shalloweroverall V-shaped hull operates in a superior manner when used inshallower waters such as bays, lakes, and sounds due to higher loadcapabilities and shallower draft plus a corresponding speed increasewith equal horsepower. Thus, both minor modifications work under thesame tunnel principles at the present invention with only a change inthe degree of efiectiveness.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention 4 plane containing the lower longitudinal thelast-mentioned outer surfaces.

r 7 to the exact construction and operation shown and described, andaccordingly all suitable modifications and equivalents may be restoredto, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A boat hull including a bottom substantially V-shaped in transversecross-section, said bottom defining a forward upwardly and forwardlycurving bow portion and a substantially longitudinally straight aftplaning portion, said planing portion of said bottom defining alongitudinal center line and at least one pair'of downwardly openinggenerally inverted V-shaped and longitudinally staright lift tunnelsextending along opposite sides of said center line, each of said tunnelsincluding inner and outer downwardly divergent surfaces including majorportions that are substantially planar, said inner surfaces beingdownwardly and inwardly inclined and said outer surfaces beingdownwardly and outwardly inclined, the angle of said inner surfacesrelative to the dead rise of said hull being less than 30 degrees andsaid outer surfaces being inclined at least degrees relative to ahorizontal plane.

2. The combination of claim 1 wherein said center line is defined by theapex of a center generally inverted V-shaped center tunnel disposedbetween said lift tunnels.

3. The combination of claim 1 wherein said center line is defined by adepending generally V-shapedcenter wedge defined by the lowermost innersurfaces.

4. The combination of claim 1 wherein said planing portion of saidbottom includes at least a first pair of opposite side generallyinverted V-shaped stabilizing tunnels disposed immediately outwardly ofthe corresponding lift tunnels and also including inner and outerdownwardly divergent surfaces including major portions that aresubstantially planar, corresponding lower longitudinal edge portions ofthe last-mentioned inner surfaces being generally disposed in saidsecond plane and below a third plane containing the lower longitudinaledge portions of the last-mentioned outer surfaces.

5. The combination of claim 4 wherein said planing portion of saidbottom includes a second pair of opposite side inverted V-shapedstabilizing tunnels, the second pair of stabilizing tunnels beingdisposed immediately outwardly of said first pair of stabilizing tunnelsand including inner and outer downwardly divergent surfaces alsoincluding major portions that are sub.- stantially planar, thecorresponding lower longitudinal edge portions of the last-mentionedinner surfaces being generally disposed in said third plane and below afourth edge portions of 6. The combination of claim 1 wherein saidplaning portion of said bottom includes at least a first pair of opposite side generally inverted V-shaped stabilizing tunnels disposedimmediately outwardly of the corresponding lift tunnels and alsoincluding inner and outer downwardly divergent surfaces including majorportions that are substantially planar, corresponding lower longitudinaledge portions of the last-mentioned inner surfaces being generallydisposed in said second plane and below a third plane containing thelower longitudinal edge portions of the last-mentioned outer surfaces,the included angles formed by corresponding inner and outer surfaces ofsaid tunnels is greater than 90 degrees.

7. The combination of claim 1 wherein the ratio of the transverse widthof said inner and outer surfaces of each of said lift tunnels measuredin a horizontal plane is at least two to one.

8. The combination of claim 1 wherein the ratio of the transverse widthof said inner and outer surfaces of each of said lift tunnels measuredalong said inner and outer surfaces is less than five to one.

9. The combination of claim 8 wherein the included angles formed bycorresponding inner and outer surfaces of said lift tunnels is greaterthan 90 degrees.

10. The combination of claim 9 wherein the ratio of the transverse widthof said inner and outer surfaces of each of said lift tunnels measuredin a horizontal plane is at least two to one.

11. The combination of claim 1 wherein. said tunnels on opposite sidesof said centerline include forward extensions thereof smoothly curvingforwardly and upwardly at their forward ends into said bow portion.

12. The combination of claim 11 wherein said forward extensions alsocurve forwardly and inwardly toward said centerline 13. The combinationof claim 1 wherein said tunnels immediately adjacent said centerline areof a width adapted to span the diameter of a marine propeller.

14. The combination of claim 1 wherein said centerline is defined by theapex of a center generally inverted V- shaped center tunnel disposedbetween said lift tunnels, said center tunnel being of a width adaptedto span the diameter of a marine propeller.

'15. The combination of claim 1 wherein said outer surfaces are inclineddownwardly and outwardly at an angle between forty and eighty degreesfrom a vertical plane. 7

16. The combination of claim 1 wherein the included angles formed bycorresponding inner and outer surfaces of said lift tunnels is greaterthan degrees.

17. The combination of claim 1 wherein the ratio Of the transverse widthof said inner and outer surfaces of each of said lift tunnels measuredalong said surfaces is between 2 to 1 and 4 to 1.

18. The combination of claim 1 wherein the ratio of the transverse widthof said inner and outer surfaces of each of said lift tunnels measuredalong a horizontal plane is between 5 to 1 and 2 to 1.

19. The combination of claim'l wherein the ratio of the transverse widthof said inner and outer surfaces of each of said tunnels measured alongsaid surfaces is at least 2 to 1.

20. A boat hull including a bottom substantially V- shaped in transversecross-section, said bottom defining a forward upwardly and forwardlycurving bow portion and a substantially longitudinally straight aftplaning portion, said planing portion of said bottom defining a longitudinal center line and at least one pair of downwardly openinggenerally inverted V-shaped and longitudinally straight lift tunnelsextending along opposite sides of'said center line, each of said tunnelsincluding inner and outer downwardly divergent surfaces including majorportions that are substantially planar, said inner surfaces beingdownwardly and inwardly inclined and said outer surfaces beingdownwardly and outwardly inclined, the in,- cluded angles formed by thecorresponding inner and outer surf-aces of said tunnels being generally90 degrees and the ratio of the transverse width of said inner and outersurfaces of each of said tunnels measured alon said surfaces being atleast 2 to 1.

21. The combination of claim 20 wherein the outer surfaces of saidtunnels are inclined at least 10 degrees relative to a horizontal plane.

References Cited UNITED STATES PATENTS Thorsen ll456 MILTON BUCHLER,Primary Examiner.

T. M. ,BLIX, Assistant Examiner.

1. A BOAT HULL INCLUDING A BOTTOM SUBSTANTIALLY V-SHAPED IN TRANSVERSECROSS-SECTION, SAID BOTTOM DEFINING A FORWARD UPWARDLY AND FORWARDLYCURVING BOW PORTION AND A SUBSTANTIALLY LONGITUDINALLY STRAIGHT AFTPLANING PORTION, SAID PLANING PORTION OF SAID BOTTOM DEFINING ALONGITUDINAL CENTER LINE AND AT LEAST ONE PAIR OF DOWNWARDLY OPENINGGENERALLY INVERTED V-SHAPED AND LONGITUDINALLY STARIGHT LIFT TUNNELSEXTENDING ALONG OPPOSITE SIDES OF SAID CENTER LINE, EACH OF SAID TUNNELSINCLUDING INNER AND OUTER DOWNWARDLY DIVERGENT SURFACES INCLUDING MAJORPORTIONS THAT ARE SUBSTANTIALLY PLANAR, SAID INNER SURFACES BEINGDOWNWARDLY AND INWARDLY INCLINED AND SAID OUTER SURFACES BEINGDOWNWARDLY AND OUTWARDLY INCLINED, THE ANGLE OF SAID INNER SURFACESRELATIVE TO THE DEAD RISE OF SAID HULL BEING LESS THAN 30 DEGREES ANDSAID OUTER SURFACES BEING INCLINED AT LEAST 10 DEGREES RELATIVE TO AHORIZONTAL PLANE.